Device for regulating the minute hand of a clock having at least a minute hand and a second hand

ABSTRACT

An arrangement for setting the minute hand of a timepiece which has at least minute and second hands  29,  having a setting stem  1  which can be moved axially out of a normal position into a setting position. In this case, upon movement of the setting stem  1  out of the normal position into the setting position, a zero setting drive of the second hand  29  can be driven such that it moves the latter into its zero position and the seconds stem  28,  which bears the second hand  29,  can be driven via a seconds-display drive mechanism  30  of the movement mechanism of the timepiece. The seconds-display drive mechanism  30  has a blocking device which can be actuated, by virtue of the setting stem  1  being moved in the direction of the setting position, such that the seconds-display drive mechanism  30  is blocked before the second hand  29  is moved into the zero position.

Arrangement for setting the minute hand of a timepiece which has atleast minute and second hands

FIELD AND BACKGROUND OF THE INVENTION

The invention relates to an arrangement for setting the minute hand of atimepiece which has at least minute and second hands, having a settingstem which can be moved axially out of a normal position into a settingposition, it being the case that, upon movement of the setting stem outof the normal position into the setting position, a zero setting driveof the second hand can be driven such that it moves the latter into itszero position and the seconds stem, which bears the second hand, can bedriven via a seconds-display drive mechanism of the movement mechanismof the timepiece.

In the case of a known arrangement of this type, the zero setting driveis a heart-cam zero setting drive which, depending on the position ofthe heart cam, moves the second hand into the zero position in theclockwise direction or the counterclockwise direction. As a result ofproduction tolerances, there is always play in the wheel train leadingto the seconds-display drive mechanism, and this play has to be overcomeupon a zero setting movement of the second hand in the counterclockwisedirection. If the second hand is then driven again in normal operation,the play in the wheel train must first be overcome before the secondhand is moved. This results in the starting of the second hand beingdelayed, and thus in the time display being incorrect by from one to twoseconds.

SUMMARY OF THE INVENTION

The objective of the invention is thus to provide an arrangement of thetype mentioned in the introduction which ensures that the second handstarts correctly following a setting operation.

This object is achieved according to the invention in that theseconds-display drive mechanism has a blocking device which can beactuated, by virtue of the setting stem being moved in the direction ofthe setting position, such that the seconds-display drive mechanism isblocked before the second hand is moved into the zero position.

This means that the seconds-display drive mechanism is blocked beforethe zero setting movement of the second hand, with the result that saiddrive mechanism always remains free of play in the normal drivedirection and ensures that the second hand starts correctly following asetting operation.

The setting stem may serve exclusively for the zero setting of thesecond hand.

If the setting stem is a minute setting stem of the timepiece and thesetting position is the minute setting position, in which, by virtue ofrotation of the setting stem, the minute hand can be driven such that itcan be moved manually, then the setting stem fulfils both the functionof initiating operation of the zero setting drive and the function ofactuating the minute setting. Movement of the setting stem into itsminute setting position alone automatically brings about zero setting ofthe second hand. In order to be able to carry out zero setting of thesecond hand without the drive of the movement mechanism being affectedthereby, the seconds stem may be coupled to the movement mechanism ofthe timepiece with a force fit. For this purpose, in a straightforwardembodiment, there may be arranged between the seconds stem and aseconds-display drive mechanism of the movement mechanism a prestressedcoupling spring which butts against at least either the seconds stem orthe seconds-display drive mechanism with a friction fit.

A space-saving embodiment is achieved in that the seconds-display drivemechanism is mounted on the seconds stem in a freely rotatable manner,it being possible, without any great amount of installation space beingrequired, for the coupling spring to be arranged axially between theseconds stem and seconds-display drive mechanism.

Both a straightforward construction of the coupling spring andconcentric loading of the components on which the coupling spring actsare achieved if the coupling spring is a spring which has one or moreradially directed spring arms, of which one spring-arm end is arrangedon the seconds stem and the second spring-arm end is supported on theend side of the seconds-display drive mechanism, it being possible forthe second spring-arm end to be supported on a radially directed,flange-like widened section of the gear wheel.

In a straightforward configuration, the blocking device may have ablocking lever which can be pivoted about a pivot spindle and which canact on a moveable drive part of the seconds-display mechanism with aforce fit and/or form fit and/or friction fit.

Fulfilling a double function, and thus saving space, the moveable drivepart may be the flange-like widened section of the seconds-display drivemechanism, of which the radially peripheral lateral surface can have theblocking lever acting on it.

The seconds-display drive mechanism is blocked particularly reliably inthat the radially peripheral lateral surface has a radially peripheralapproximately V-shaped groove into which the blocking lever, which canbe pivoted about the pivot spindle parallel to the axis of rotation ofthe seconds-display drive mechanism, can be pivoted by way of anapproximately V-shaped blocking region.

A reliably functioning construction of straightforward configuration isachieved if the zero setting drive is a cam-plate drive, of which thecam plate is arranged fixedly on the seconds stem, which bears thesecond hand, and, upon movement of the setting stem in the direction ofthe setting position, can be driven such that it can be moved into thezero position by a zero setting lever, for which purpose the cam-platedrive is preferably a heart-cam zero setting drive. If the cam plate canbe arrested in the zero position by the zero setting lever, then thesecomponents serve not just for movement into the zero position, but alsofor keeping the second hand in the zero position.

Just a small amount of installation space is required if the zerosetting lever is a lever which can be pivoted about a spindle parallelto the seconds stem and which acts on the radially peripheral lateralsurface of the cam plate.

A straightforward and space-saving setting drive is achieved in that thezero setting drive has a pivot lever which can be pivoted, about a pivotspindle parallel to the seconds stem, between a normal position and azero setting position, which is forced into its zero setting position byspring action and which can act on the zero setting lever such that itcan be moved out of its normal position, in which it is spaced apartfrom the cam plate, against the cam plate.

If the blocking lever can be driven such that it can be pivoted by thepivot lever, then the pivot lever fulfils more than one function at thesame time.

Blocking of the seconds-display drive mechanism before the second handis moved into the zero position is achieved, in a straightforwardconstruction, in that the pivot spindle of the blocking lever and thespindle of the zero setting lever are arranged axially with respect toone another, and the blocking engagement direction of the blocking leverand the zero setting direction of the zero setting lever are oriented inapproximately the same way.

If the action of a blocking spring forces the blocking lever both in theblocking engagement direction and against the pivot lever, such that thelatter is forced into the zero setting position, then the blockinglever, following its blocking engagement, can easily be released fromthe pivot lever and this can move on further in relation to the camplate of the cam-plate drive. For this purpose, a straightforwardconstruction consists in that the action of the blocking spring forcesthe blocking lever into abutment against a stop of the pivot lever or ofthe zero setting lever, it being the case that, when the blocking leverand pivot lever are respectively pivoted in the blocking engagementdirection and the zero setting direction, the blocking lever reaches theblocking position before the zero setting lever reaches the zero settingposition.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention is described in more detailhereinbelow and is illustrated in the drawings, in which:

FIG. 1 shows the normal position of an arrangement for setting theminute hand of a timepiece which has a minute hand and second hand;

FIG. 2 shows the arrangement according to FIG. 1 in the settingposition;

FIG. 3 shows a detail of the arrangement according to FIG. 1 in anintermediate position between the normal position and setting position;and

FIG. 4 shows a side view in the section along line II—II in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The arrangement illustrated has a setting stem 1 which can be displacedmanually in the axial direction between a normal position (FIG. 1) and asetting position (FIG. 2).

The setting stem, in its setting position, is incorporated in aminute-hand drive (not illustrated) and, by virtue of the rotation ofthe setting stem 1 about its axis of rotation, can adjust the positionof a minute hand (not illustrated either).

A pin 2 of an angle lever 4, which can be pivoted about a spindle 3,engages, transversely with respect to the axis of rotation of thesetting stem 1, in an annular groove 5 formed around the periphery, inthe radial direction, of the setting stem 1. By virtue of axialdisplacement of the setting stem 1, the angle lever 4 is pivoted aboutits spindle 3 via the pin 2.

A catch spring 7 acts on an extension 6, which projects from the anglelever 4, such that, depending on its pivot position , the angle lever 4is forced into its rest position or its operation-initiating position orits hand setting position. The catch spring 7 comprises a spring arm 8which is arranged in a fixed manner at one end and has a tooth 9 at itsother end.

In the rest position the tooth 9 abuts against the extension 6 by way ofone flank, and in the operation-initiating position it butts against thesame by way of its other flank. Upon pivoting of the angle lever 4, thespring arm 8 is deflected, with the result that the tooth 9 is movedbeyond the extension 6 (FIG. 3).

On its lever arm opposite the setting stem 1, the angle lever 4 bears astub 10 which engages in a groove 11 of a control plate 12.

The control plate 12 can be pivoted about a spindle 13 parallel to thespindle 3 of the angle lever 4, it being the case that the pivot path islimited by the ends of the groove 11, the stub 10 coming into abutmentagainst said ends. In this case, the groove 11 is equidistant from thespindle 13.

The control plate 12 has a control curve 14 which is likewiseequidistant from the spindle 13. This control curve 14, which isdesigned as an arc section, interacts with an activation surface 15 of apivot lever 16 which can be pivoted about a pivot spindle 17 by thecontrol curve 14.

For this purpose, the activation surface 15 is designed as a slope whichis inclined with respect to a radial line to the pivot spindle 17 of thepivot lever 16. In this case the control curve 14 and activation surface15 are inclined with respect to one another at such an angle thatself-locking of the two parts sliding on one another is ruled out.

The pivot lever 16, by way of an activation surface 15, is forcedpermanently in the direction of the control curve 14 by the action ofthe free end of a prestressed spring arm 18 and, in the normal position(FIG. 1), rests on the control curve 14 in a prestressed manner by wayof the activation surface 15.

However sliding of the control curve 14 along the activation surface 15,and thus pivoting of the pivot lever 16, is only possible when the anglelever 4 is pivoted by virtue of the setting stem 1 being moved out ofthe normal position into the setting position. In this case, the controlcurve 14, under the action of the force of the spring arm 18 on thepivot lever 16, slides along the activation surface 15 until, at the endof its pivot path, it is disengaged from the activation surface 15,since the ability of the pivot lever 16 to pivot is limited.

The pivot lever 16 is designed as a two-armed lever, on one lever arm ofwhich the activation surface 15 is arranged. The other lever arm isbranched into a zero setting arm 19 and a stopping arm 20. A zerosetting lever 22 is arranged in a plane parallel to the zero setting arm19, such that it can be pivoted about a spindle 21 parallel to the pivotspindle 17. In this case, the spindle 21 is located at one end of thezero setting lever 22, while arranged at the other end of the zerosetting lever 22, directed in the pivot direction, is a setting surface23.

Arranged approximately centrally between the setting surface 23 andspindle 21, on the zero setting lever 22, is a pin 24 which extendsparallel to the spindle 21 and projects into the pivot region of thepivot lever 16. The pin 24 has a fork-shaped end 25 of the zero settingarm 19 engaging around it, and the pivot position of the zero settinglever 22 is thus determined by the zero setting arm 19.

When the pivot lever 16 is pivoted out of the normal position into thezero setting position, the fork-shaped end 25 of the zero setting arm 19pivots the zero setting lever 22 into abutment against a stop 26. Inthis case, the setting surface 23 passes into the region of a heart-camplate 27 which is arranged in a rotationally fixed manner on a secondsstem 28 parallel to the spindle 21.

By virtue of the action of the setting surface 23 on the radiallyperipheral lateral surface of the heart-cam plate 27, the heart-camplate 27 is pivoted until the setting surface 23 reaches the locationwhich is nearest the axis of rotation of the heart-cam plate 27 in theradial direction. As a result, however, the second hand 29, which isarranged on the seconds stem 28, is also moved into its zero position.

This pivoting of the seconds stem 28 can be carried without obstructionsince a seconds-display drive mechanism 30 of the wheel train of themovement mechanism is mounted on the seconds stem 28 in a freelyrotatable manner and is only coupled to the seconds stem 28 by acoupling spring 31 with a force fit. As a result, by virtue of the forcefit of the coupling spring 31 being overcome, the seconds stem 28 can berotated without being blocked by the seconds-display drive mechanism 30.

The coupling spring 31 is of leaf-spring design with a central part 33,from which there project three radially extending spring arms 34 whichare angled out of the plane of the central part 33. The coupling spring31 is arranged on the seconds stem 28 by way of a bore 35 formed in thecentral part 33. In this case, the central part 33 is supported on theheart-cam plate 27, while the free ends of the spring arms 34 aresupported with prestressing on a radially directed, flange-like widenedsection 36 of the seconds-display drive mechanism 30. By virtue of theheart-cam plate 27 and seconds-display drive mechanism 30 being rotatedrelative to one another with sufficient force, it is possible toovercome the force-fit coupling between the central part 33 of thecoupling spring 31 and the heart-cam plate 27 and the seconds-displaydrive mechanism 30.

At its free end, the stopping arm 20 of the pivot lever 16 has a pin 37which projects transversely with respect to the pivot plane of saidlever. This pin 37 interacts, counter to the force of a spring 40, witha stopping lever 39 which can be pivoted about a pivot spindle 38. One,free end of the stopping lever 39 is designed as a spring arm 41 and, byvirtue of the stopping lever 39 being pivoted by the spring 40, can bemoved into abutment against the radially peripheral contour of a balancewheel 42. The resilient abutment of the spring arm 41 against thebalance wheel 42 means that the rotary movement of the latter can bestopped. In the normal position of the pivot lever 16, the pin 37 of thestopping arm 20 butts against a stop surface 43 of the stopping lever 39and thus keeps the spring arm 41 of the stopping lever 39, counter tothe force of the spring 40, at a distance from the balance wheel 42,with the result that the latter can move freely.

By virtue of the pivot lever 16 being pivoted into the zero settingposition, the pin 37 of the stopping arm 20 is disengaged from thestopping lever 39, with the result that the spring 40 pivots thestopping lever 39 and the latter, by way of its spring arm 41, comesinto abutment, with prestressing, against the radially peripheralcontour of the balance wheel 42 and blocks the movement of the balancewheel 42. The movement mechanism of the timepiece is also put out ofoperation as a result.

A blocking lever 45 is arranged such that it can be pivoted about apivot spindle 44 parallel to the spindle 21 of the zero setting lever22.

By virtue of a blocking spring 46, the blocking lever 45 can be moved,by way of its free end, against the radially peripheral lateral surfaceof the flange-like widened section 36. At this free end, the blockinglever 45 has an approximately V-shaped blocking region 47 by means ofwhich it can be pivoted into an approximately V-shaped groove 48, whichis formed around the periphery, in the radial direction, of the radiallyperipheral lateral surface of the widened section 36.

In the normal position (FIG. 1), the pin 24 of the zero setting lever 22keeps the blocking region 47 of the blocking lever 45 disengaged fromthe groove 48 counter to the force of the blocking spring 46.

If the zero setting lever 22 is pivoted, by the pivot lever 16, out ofthe normal position into the zero setting position, then the blockinglever 45, which is supported on the pin 24, follows until it engages inthe groove 48 by way of its blocking region 47 and thus blocks theseconds-display drive mechanism 30.

The zero setting lever 22 is then moved on further by the pivot lever 16until it comes to rest, by way of its setting surface 23, on theheart-cam plate 27 and rotates the latter until the setting surface 23butts against the radially lowest point of the heart-cam plate 27 andthe second hand 29 is thus located in its zero position.

In this case, the seconds-display drive mechanism 30 is blocked beforethe heart-cam plate 27 is adjusted.

For the purpose of setting the timepiece to the right time, first of allthe setting stem 1 is drawn upward, by means of a winder (notillustrated), out of the normal position, which is illustrated in FIG.1, into the setting position, which is illustrated in FIG. 2.

As a result, the angle lever 4 is pivoted in the counterclockwisedirection and transmits its movement to the control plate 12. Until theintermediate position, which is illustrated in FIG. 3 has been reached,the angle between the control curve 14 and the activation surface 15 issuch that there is self-locking between the two abutting parts. As thecontrol curve 14 is pivoted further, the pivot lever 16 is also pivoted,with the result that the angle between the control curve 14 andactivation surface 15 changes such that self-locking of these twoabutting parts is now ruled out. Under the force of the spring arm 18,the pivot lever 16 then automatically slides along the control curve 14by way of its activation surface 15 and, in the process, pivots suchthat it moves over the pin 24 of the zero setting lever 22 by way of itsfork-shaped end 25 and releases the blocking lever 45, with the resultthat the latter follows the zero setting lever 22 under the action ofthe blocking spring 46.

As a result, first of all the seconds-display drive mechanism isblocked. Then the zero setting lever 22 acts on the heart-cam plate 27by way of its setting surface 23 and, overcoming the frictional forcesof the coupling spring 31, said heart-cam plate 27 is moved directlyinto the zero position and is secured there.

At the same time, the stopping lever 39 is pivoted, by way of its springarm 41, against the balance wheel 42 by the stopping arm 20 of the pivotlever 16 and stops said balance wheel.

Then, by virtue of rotation of the setting stem 1, a minute hand (notillustrated) and an hour hand (not illustrated either) are set to thecorrect time, e.g. of the next time signal.

When this time signal sounds, then the setting stem 1 is displaced intothe normal position again, as a result of which the angle lever 4 and,following passage through a certain free path of the angle lever 4, viathe control plate 12, the pivot lever 16 and the zero setting lever 22,by way of its setting surface 23, are forced back into their normalpositions, as a result of which the heart-cam plate 27 is released.

The pin 24 then lifts the blocking lever 45, with the result that theblocking region 47 of the latter is moved out of the groove 48 and theseconds-display drive mechanism 30 is released.

At the same time, the stopping arm 20 acts on the stop surface 43 of thestopping lever 39, lifts off the spring arm 41 of the latter from thebalance wheel 42 and releases said balance wheel.

As a result, the movement mechanism of the timepiece runs freely and thehands move synchronously.

For the purpose of adjusting the lever paths, use is made of aneccentric 50 on the pivot spindle 17 for the pivot lever 16, of aneccentric 51 on the stop 26 of the zero setting lever 22, and of aneccentric 52 on the pivot spindle 44 of the blocking lever 45.

Of course, the seconds-display drive mechanism which is to be blockedneed not necessarily be the drive mechanism which is seated on theseconds stem; rather, it is also possible for it to be a gear wheelwhich is in the vicinity of said drive mechanism and is located in thewheel train which leads to said drive mechanism. However, it is best ifit is the drive mechanism which is seated on the seconds stem which isblocked.

What is claimed is:
 1. An arrangement for setting a minute hand of atimepiece which has at least minute and second hands, comprising amovment mechanism, a setting stem which is movable axially out of anormal position into a setting position, a zero setting drive of thesecond hand, a seconds-display drive mechanism of the movement mechanismof the timepiece, wherein upon movement of the setting stem out of thenormal position into the setting position, said zero setting drive ofthe second hand is drivable such that the latter is moved thereby into azero position thereof, and a seconds stem bears the second hand, saidseconds stem is drivable via said seconds-display drive mechanism of themovement mechanism of the timepiece, wherein the seconds-display drivemechanism (30) has a blocking device, said blocking device is actuatableby the setting stem (1) being moved in direction of the settingposition, such that the seconds-display drive mechanism (30) is blockedbefore the second hand (29) is moved into the zero position.
 2. Thearrangement as claimed in claim 1, wherein the setting stem (1) is aminute setting stem of the timepiece and the setting position is theminute setting position, in which, by rotation of the setting stem (1),the minute hand is drivable such that it is movable manually.
 3. Thearrangement as claimed in claim 1, wherein the seconds stem (28) iscoupled to the movement mechanism of the timepiece by action of force.4. The arrangement as claimed in claim 3, further comprising aprestressed coupling spring (31), and wherein arranged between theseconds stem (28) and said seconds-display drive mechanism (30) of themovement mechanism is said prestressed coupling spring (31) which abutsagainst at least either the seconds stem (28) or the seconds-displaydrive mechanism (30) with a friction fit.
 5. The arrangement as claimedin claim 4, wherein the seconds-display drive mechanism (30) is freelyrotatably mounted on the seconds stem (28).
 6. The arrangement asclaimed in claim 5, wherein the coupling spring (31) is arranged axiallybetween the seconds stem (28) and said seconds-display drive mechanism(30).
 7. The arrangement as claimed in claim 6, wherein the couplingspring (31) is a spring which has at least one radially directed springarms, of said siring arms one spring-arm end is arranged on the secondsstem (28) and a second spring-arm end is supported on an end side ofseconds-display drive mechanism (30).
 8. The arrangement as claimed inclaim 7, further comprising a radially directed flange-like widenedsection (36) of the seconds-display drive mechanism (30) wherein thesecond spring-arm end is supported on said radially directed flange-likewidened section (36) of the seconds-display drive mechanism (30).
 9. Thearrangement as claimed in claim 1, further comprising a pivot spindle(44), and a moveable drive part of the seconds-display drive mechanism(30), wherein the blocking device has a blocking lever (45) which ispivotable about said pivot spindle (44) and which is actable on saidmoveable drive part of the seconds-display drive mechanism (30).
 10. Thearrangement as claimed in claim 9, further comprising a flange-likewidened section (36) of the seconds-display mechanism (30), wherein themoveable drive part is the flange-like widened section (36) of theseconds-indicating drive mechanism (30), the blocking lever (45) beingactable on a radially peripheral lateral surface thereof.
 11. Thearrangement as claimed in claim 10, further comprising a gear wheel, andwherein the radially peripheral lateral surface has a radiallyperipheral, approximately V-shaped groove (48) into which the blockinglever (45), which is pivotable about the pivot spindle (44), parallel toan axis of rotation of the gear wheel, is pivotable by an approximatelyV-shaped blocking region (47).
 12. The arrangement as claimed in claim1, further comprising a zero setting lever (22), wherein the zerosetting drive is a cam-plate drive, a cam plate of the cam-plate driveis arranged fixedly on the seconds stem (28), and, upon movement of thesetting stem (1) in the direction of the setting position, is drivablesuch that it is movable into the zero position by said zero settinglever (22).
 13. The arrangement as claimed in claim 12, wherein saidcam-plate drive is a heart-cam zero setting drive.
 14. The arrangementas claimed in claim 13, further comprising a spindle (21), wherein thezero setting lever (22) is a lever which about said spindle (21)parallel to the seconds stem (28) and which acts on a radiallyperipheral lateral surface of the cam plate.
 15. The arrangement asclaimed in claim 12, further comprising a pivot spindle (17), whereinthe zero setting drive has a pivot lever (16) which is pivotable aboutsaid pivot spindle (17) parallel to the seconds stem (28), between anormal position and a zero setting position, which is forced into saidzero setting position thereof by spring action and which is actable onthe zero setting lever (22) such that it is movable out of its normalposition, in which it is spaced apart from the cam plate, against thecam plate.
 16. The arrangement as claimed in claim 9, wherein theblocking lever (45) is drivable such that it is pivotable by the pivotlever (16).
 17. The arrangement as claimed in claim 9, furthercomprising a zero setting lever (22) and a spindle (21), wherein thezero setting lever (22) is pivotal about said spindle (21), and whereinthe pivot spindle (44) of the blocking lever (45) and the spindle (21)of the zero setting lever (22) are arranged axially with respect to oneanother, and a blocking engagement direction of the blocking lever (45)and a zero setting direction of the zero setting lever (22) are orientedapproximately the same.
 18. The arrangement as claimed in claim 17,further comprising a blocking spring (46), and wherein the zero settingdrive has a pivot lever (16), wherein action of said blocking spring(46) forces the blocking lever (45) both in the blocking engagementdirection and against the pivot lever (16), such that the latter isforced into a zero setting position.
 19. The arrangement as claimed inclaim 18, wherein said pivot lever (16) or said zero setting lever (22)has a stop, wherein action of the blocking spring (46) forces theblocking lever (45) into abutment against said stop of the pivot lever(16) or of the zero setting lever (22), wherein, when the blocking lever(45) and pivot lever (16) are respectively pivoted in the blockingengagement direction and the zero setting direction, the blocking lever(45) reaches blocking position before the zero setting lever (22)reaches the zero setting position.
 20. The arrangement as claimed inclaim 1, further comprising a pivot spindle (44) and a moveable drivepart of the seconds-display drive mechanism (30), wherein the blockingdevice has a blocking lever (45) which is pivotable about said pivotspindle (44) and which is actable on said moveable drive part of theseconds-display drive mechanism (30) with a force, form of cooperatingparts or friction fit.